Electric handsaw



Nov. 3, 1931. F. w. WAPPAT' ELECTRIC HANDSAW Filed Aug. 16, 1930 2 Sheets-Sheet l Nov. 3/1931. '1 w. wAPPAf 30,580

, .';VELECTRIC HANDSAW Filed Aug. 15, 1930 2 Sheets-Sheet 2 v. min

INVENTOR L gu ' the motor is avoided; (3) the Patented Nov. 3, 1931 UNIT D STATES PATENT OFFICE FEED W. wAIPAT, OF PITTSBURGH, PENIFTSYLVANIA, ASSIGNOR TO WAIPPAT, INCOR- PORATED, A CORPORATION OF PENNSYLVANIA ELECTRIC HANDSAW Application filed August 16, 1930. Serial No. 475,687;

The invention relates to electric handsaws and involves certain improvements over the constructions of my Patent No. 1,623,290 and application Serial No. 424,551, filed January 30, 1930. It has for its principal objects; (1) the provision of means which come into play when cutting at an angle whereby the guard is retracted by the tilting of the saw frame so that it will not interfere with the action of the 10 saw at such time; (2) the provision of safety means in connection with the hand lever carried in the handle of the saw for operating the electric switch whereby accidental starting of provision of 16 means whereby said lever may e locked in o erative position under certain conditions use in order to relieve the operator of the necessity of holding the lever in such position; and (4) the provision of improved '20 means. for gauging the position of the saw with respect to the work andguiding it during the cutting operation. One embodiment of the invention is illustrated in the accompan-ying drawings, wherein: Figure 1 is a perspective view of the saw in what may be termed normal osition of use. Fig. 2 is "a perspective view s owing the saw in another (mitering) position of use. Fig. 3 is a partial perspectivewiew of the saw 80 showing the operation of the device for retracting the saw guard when the saw is adjusted to cut at an angle just as the cut is started. Fig. 4 is a detail sectional view showing the guard retracting device. Fig. 5 is a detail sectional view through the handle showing the safety device in locking position preventingthe accidental operation of the switch lever. Fig. 6 is a detail sectional view similar to that of Fig. 5, but showing the parts in operating position. Fig. 7 is another section showing the parts locked in operating position. And Fig. 8 is a front view of the machine.

Referring to the drawin s, 1 is the saw frame provided at one end with the handle 2;

3 (Fig. 8) is an electric motor suitably mounted in the frame and provided with a shaft 4 carrying the worm 5; 6 is a shaft extending transversely of the frame and carrying the 50 worm wheel 7 and the circular saw 8; 9 is a guard or shield integral'with the frame and surrounding the upper half of the saw; and 10 is a movable guard casing or shield similar to that of my patent heretofore referred to, said guard or shield being pivoted on the frame concentric with the axis of rotation of the saw or approximately so and being adapted to. telescope into the fixed casing when swung to the rear.

The saw frame is provided at its front end with an arm 12, and to this arm is secured the bracket 13 by means of the pivot pin 14 (Fig. 1). The machine is provided with a base plate 15, which governs both the depth of the cut of the saw and the angle of such out, such as base plate being cut away to permit of the adjustmentof the saw and guard 10 therethrough and being pivoted at its front end to the bracket 13 by means of the pin 16. The base plate has secured to its front end a plate 17 provided with a slot 18 in which slides the bolt 19 secured to the bracket 13. The bolt carries a clamping nut 20 for holding the base plate in any desired position of adjustment with respect to the bracket 13.

A second bracket 21 provides for the adj ustment of the base plate 15 to vary the de th of cut' y' the saw. This bracket is secure at its lower end to the base plate by means of the pivot pin 22 (Fig. 1). It is rovided with 80 a slot 23 through which exten s a clamping Y bolt 24 threaded into the saw frame. The pivots 16 and 22 are in ali out with each other and lie just to one si e of the plane of the saw 8. The adjustment of the saw frame around these pivots gives the saw its various angles in cutting miters, the nut 20 on the bolt 19 serving to clamp the base plate in its position relative to the saw frame during the sawing operation.

Fig.1 shows the parts adjusted so that the saw will cut at right angles to the plane of the upper face of the plank 25 and with a maximum depth of cut, the bracket 21 being at its uppermost position of adjustment. To cut at a less depth and at an angle of about 60 degrees to the upper face of the plank 25, the parts are adjusted to the (position of Fig. 2, the base plate being tilte on the pivots 16 and 22 to the position shown, and the 100 bracket 21 being moved down and clamped.

When the saw is used. to ,cut at an angle such as shown in Fig. 2 and approaches the end of the plank at an acute angle from left to right, the nose of the guard will strike the end of the planir andj'preventthe' saw from engagihg tlfemlankfi In order to retract the guard under such conditions, an arm 26 is provided on the guard above the lug 27 on'the'base plate 15." frame is tilted, as indicated in guard so that the saw can engage the plank without interference with the-work. [After the saw has cut into the plank, the end of such plank en'gages'theendof thegrrard and gives it'an'y 'fdrther'innvement of+retractionwhieh'isneeessary." Encept un'der the con' ditionsabove recited, the parts26 and 27do not co'me in't'o play, the nard"bei ng pushed bacltfr'om' 'thei'begirining by 'the-end'ofthe plank as thesaw'advances; *As in my Patent o."1,623,290, a spring (not shown) is'provided tending to rotate the guard 10 in a counter "clockwise" direction so that it "occupie's'the position shown in'Figfi2 with a shoulder -at 28 engaging a stop lug 29 car ried by the'saw frame.

The base plate is providedat' its front end with 'a pair of perforate lugs 30, 30 in which is mounted a gauge rod'31 *(shown in FigsI 1-and'8 but removed in Fig. 2),. such rod being 'hdjustable 'endwise and provided at oneend with' astopmember 32' forenaging the side edge of the plank 25. A set screw-33 'servesto clamp the rod in any desired position "of adjustment. The use of this gauge assists in guiding the saw so as to make 'a'straight cut parallel to'the side edge of the plank. The device is convenient when it is desired to 'cut thin stripbecanse theend 32 lies base plate.

The device for operating-the switch which starts andstops the motor is shown in Figs. 5, 6,"and 7, wherein 34 is a snap switch having a trigger 35 operated by the slide rod 36, and 37 is anoperating lever pivoted at 38 inthe handle 2; The switch'is so constructed that the trigger 'is yieldingly held in the full line "position of Fig.6, at which time the circuit to themotor is interrupted. When this -trigger is moved to the right, the circuitis completed. The-lever is moved to start the motor by the operator squeezing the handle, thus moving the rod 36 to the right (Figi 5), the position thus assumed by the-lever being that shown in Fig. 6. In order to prevent the motor from being startedacc'ide'ntallywhen the operator grasps the handieto move the machine, the detent 39 pivoted at 40 and normally pressed to the positi'on'shown in Fig. 5 by the spring 41 is providedf The end of this detent engages a shoulder 42 on the lever, thus preventing it also very off a very below the en the saw Figs; and 3, I the arm engages the lug and retracts the clamped-in--such-position in order to use its base plate as a saw table over which the member's 'tobe-cut are 'movedg and in order to so lock-the lever 'it is provided with a to its on position,

shtiulder'ei adapted to'be engaged and held by the recess 45 in the detent when the parts are moved to'the' position-of Fig. 7. This engagement is secured by pushing the thumb piece 43down from the positionofFig. 6 and allo wing the lever to swing tothe left from the position of Fig. 6 -to the-positlon of Fig. 7 so that the shoulder engages the recess;- To release the parts and allowthem to comeback to the position of Fig. 5, the lever 37 is swung to the right at which time the spring 41 swings" the detent back to such position.

WVhatI claimis:

1. In combination-in'an electric hand saw,

a saw frame, a saw-mounted for rotation thereim'la motor in the frame for driving the saw, a shield also carried by the saw frame and covering the'upper part of the'saw, a guard mounted forswinging movement about' the axis of rotation of the-saw and yieldingly held in forward position protectingtheldwer part'of 'the'saw, a base-plate through which'the-saw and said guard project mounted for tilting movement on the saw frame so as toprovide for miter cuts by the saw, and an arm carried by the rear por-' tion of the-guard above'the base plate ositioned I so that such arm engages the ase plate and causes a movement of the guard to the rear when the base plate is tilted to mitering position.

' 2. In combination in an electric hand saw, asaw frame, a saw mounted for rotation therein. a motor on the'frame for driving the saw. a shield also carried by the saw frame and covering the upper part of the saw, a guard mounted for swinging movement about the axis ofrotation of the saw and yieldingly held in forward position protecting the lower part of the saw, a base plate through which the saw and said guard project mounted for tilting movement on the saw frame so as to provide for miter cuts by the saw, and interengaging means between the base plate and guard arranged the base plate is tilted on the saw frame to. a mitering position.

3. In combination in an electric hand saw, a saw frame, a saw mounted for rotaiion therein, a motor on the frame for driving the saw, a shield also carried by the saw frame and covering the upper part oi the saw, a guard mounted for swinging movement about the axis of rotation of the saw and vieldingly held in forward position protecting the lower part of the saw, a base late adapted to contact with the surface 0 the "work to be cut and guide the saw in its movement therethrough, having pivotal connection with the saw frame, and inter-engaging means between the base plate and guard arranged so that the guard is moved to the rear when the base plate is tilted with respect to the saw frame to a mitering position.

In testimony whereof, I have hereunto subscribed my name this 14th day of August, 1930.

FRED W. WAPPAT. 

